When performing catheterization procedures, such an angiography or angioplasty, a catheter is generally introduced percutaneously (i.e., through the skin) into the vascular system by first penetrating the skin and underlying tissue, and then the blood vessel, with a sharpened hollow needle. Location of a blood vessel, such as an artery, is typically achieved by feeling for the pulse, since such structures usually cannot be seen through the skin. Next, a guide wire is commonly inserted through the lumen of the hollow needle and is caused to enter the selected blood vessel. Subsequently, the needle is typically slid off the guide wire and a combination of a dilator and sheath are fed over the guide wire and pushed through the skin to enter the vessel. The guide wire and dilator can then be removed and the desired catheter to carry out the procedure is fed through the lumen of the sheath and advanced through the vascular system until the working end of the catheter is appropriately positioned. Following the conclusion of the catheterization procedure, the working catheter will be withdrawn and, subsequently, the sheath can also be removed from the wound, or left in place to facilitate closure.
At this point in the procedure, the vessel leakage is controlled in order to stem the flow of blood through the puncture. Because it is common practice to administer a blood thinning agent to the patient prior to many of the catheterization procedures, stemming the blood flow can be troublesome. A common method of sealing the wound is to maintain external pressure over the vessel until the puncture naturally seals. This method of puncture closure typically takes at least thirty minutes, with the length of time usually being substantially greater if the patient is hypertensive or anti-coagulated. In some anti-coagulated patients, the sheath is left in place for hours to allow the anti-coagulant to wear off. When human hand pressure is utilized, it can be uncomfortable for the patient and can use costly professional time on the part of the hospital staff. Other pressure techniques, such as pressure bandages, sandbags or clamps, have been employed, but these devices also require the patient to remain motionless for an extended period of time and the patient must be closely monitored to ensure their effectiveness.
An alternative method for wound closure includes the use of a percutaneous suturing device, such as is described by co-pending U.S. Provisional Patent Application Ser. No. 60/343,786, entitled Vascular Suturing Device, filed Oct. 22, 2001 and assigned to the common assignee hereof and incorporated by reference herein in its entirety. The percutaneous suturing device described by that application is a device for closure of a wound in a patient, such as a puncture hole in a blood vessel. The apparatus, illustrated generally at 10 in FIG. 1, includes a housing, shown generally at 12, a shaft 14 having first 16 and second 18 ends in which the first end 16 is coupled to the housing 12, a tissue engaging section 20 coupled to the second end 18 of the shaft 14, and first 22 and second 24 needles which extend from the housing 12 through the shaft 14 into the tissue engaging section 20. The tissue engaging section 20 is directed through the wound, and has first 26 and second 28 gaps (best seen in FIG. 2) in which each gap has opposing surfaces into which different sides of the wound can be received. The first needle 22 is extendable into a holder 30 through the first gap 26 to capture one of the two ends of a suture material or thread (not shown), and is retractable with the captured suture. The second needle 24 is extendable into another holder 32 through the second gap 28 to capture the opposite end of the suture material (not shown), and is retractable with the captured suture. A selecting mechanism 34 (FIG. 1) determines which of the first or second needles 22, 24 are can be driven. The user operates an actuator member 36 to drive and retract each of the selected needles to retrieve each end of the suture material through the tissue about the wound. The actuator member is biased into an extended position (non-needle driving position) by springs 38, 40. A flexible distal member 42 is shown extending distally from the tissue engaging section 20. The flexible distal member 42 (FIGS. 1 and 3) may include a channel 44 extending through at least a portion of the member for receipt of a guide wire (not shown).
Percutaneous devices, such as the suturing device described in the above-referenced co-pending application, as well as other devices not specifically enumerated, are generally introduced percutaneously through introducer sheaths, which must first be inserted into a vessel dilated to the size of the introducer sheath. The introducer sheaths have significantly larger diameters than the tool to be introduced into the vessel to facilitate introduction and removal of the device there from. For example, a 6 French device may require a 9 French or larger introducer at the wound site.
There remains a need in the art for more effective and efficient methods of introducing percutaneous devices.